From 3d8cd9b064b6131220531914edc93a6c8f29ac7e Mon Sep 17 00:00:00 2001
From: Oleg Babichev <oleg.babichev@jetbrains.com>
Date: Mon, 4 Nov 2024 14:39:13 +0100
Subject: [PATCH] Review issues: eliminate AliasOnlyExpression interface

---
 .../kotlin/org/jetbrains/exposed/sql/Alias.kt | 22 +++++++++----------
 .../kotlin/org/jetbrains/exposed/sql/Table.kt | 15 +++----------
 2 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Alias.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Alias.kt
index ef9cf763d6..0ad2e0fa8f 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Alias.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Alias.kt
@@ -123,28 +123,19 @@ class ExpressionAlias<T>(val delegate: Expression<T>, val alias: String) : Expre
     /** Returns an [Expression] containing only the string representation of this [alias]. */
     fun aliasOnlyExpression(): Expression<T> {
         return if (delegate is ExpressionWithColumnType<T>) {
-            object : AliasOnlyExpression<T>, Function<T>(delegate.columnType) {
-                override val origin: ExpressionAlias<T> = this@ExpressionAlias
-
+            object : Function<T>(delegate.columnType) {
                 override fun toQueryBuilder(queryBuilder: QueryBuilder) = queryBuilder { append(alias) }
             }
         } else {
-            object : AliasOnlyExpression<T>, Expression<T>() {
-                override val origin: ExpressionAlias<T> = this@ExpressionAlias
-
+            object : Expression<T>() {
                 override fun toQueryBuilder(queryBuilder: QueryBuilder) = queryBuilder { append(alias) }
             }
         }
     }
 }
 
-internal interface AliasOnlyExpression<T> {
-    val origin: ExpressionAlias<T>
-}
-
 /** Represents a temporary SQL identifier, [alias], for a [query]. */
 class QueryAlias(val query: AbstractQuery<*>, val alias: String) : ColumnSet() {
-
     override fun describe(s: Transaction, queryBuilder: QueryBuilder) = queryBuilder {
         append("(")
         query.prepareSQL(queryBuilder)
@@ -170,6 +161,15 @@ class QueryAlias(val query: AbstractQuery<*>, val alias: String) : ColumnSet() {
             ?: error("Field not found in original table fields")
     }
 
+    internal val aliasedFields: List<Expression<*>>
+        get() = query.set.fields.map { expression ->
+            when (expression) {
+                is Column<*> -> expression.clone()
+                is ExpressionAlias<*> -> expression.delegate.alias("$alias.${expression.alias}").aliasOnlyExpression()
+                else -> expression
+            }
+        }
+
     override fun join(
         otherTable: ColumnSet,
         joinType: JoinType,
diff --git a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Table.kt b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Table.kt
index 14b48628ea..11171dac14 100644
--- a/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Table.kt
+++ b/exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Table.kt
@@ -247,18 +247,9 @@ class Join(
         ) { it.joinPart.columns }
 
     override val fields: List<Expression<*>>
-        get() = joinParts.flatMapTo(
-            table.fields.toMutableList()
-        ) {
-            when {
-                it.joinPart is QueryAlias ->
-                    it.joinPart.fields.map { field ->
-                        when (field) {
-                            is AliasOnlyExpression<*> ->
-                                field.alias("${it.joinPart.alias}.${field.origin.alias}").aliasOnlyExpression()
-                            else -> field
-                        }
-                    }
+        get() = joinParts.flatMapTo(table.fields.toMutableList()) {
+            when (it.joinPart) {
+                is QueryAlias -> it.joinPart.aliasedFields
                 else -> it.joinPart.fields
             }
         }